Image pickup device and image pickup lens

ABSTRACT

An image pickup device provided on a base board, comprises an image pickup element provided on the base board and including a photoelectrically converting section in which pixels are arranged, a peripheral surface formed around the photoelectrically converting section and a side surface crossing the peripheral surface; an optical member including a lens section to form an image of an object onto the photoelectrically converting section of the image pickup element, a leg section to support the lens section and a contact surface to be brought in contact with the image pickup element, wherein the lens section, the leg section and the contact surface are made in a single body. The optical member is mounted on the image pickup element such that the contact surface is brought in contact with the peripheral surface or with a surface member when the surface member is provided on the peripheral surface.

This is a continuation of application Ser. No. 10/040,437, filed Jan. 9,2002 now U.S. Pat. No. 7,528,880 and Priority of Application Nos.2001-004706, filed on Jan. 12, 2001; 2001-033111, filed Feb. 9, 2001;2001-148912, filed May 18, 2001; 2001-155083, filed May 24, 2001 inJapan is claimed Under 35 U.S.C. §119, all of which are incorporatedherein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to an image pickup device, and moreparticularly, to an image pickup device capable of being mounted on acell phone and a personal computer.

In recent years, highly efficient CPUs, advanced image processingtechnologies and others have made it possible to handle digital imagedata easily. In the field of a cell phone and PDA, in particular, a typethat is equipped with a display capable of displaying an image hasappeared on the market, and rapid progress in radio-communication speedis expected in the near future, which makes us to estimate thattransmission of image data will be conducted frequently between thesecell phones and PDAs.

Incidentally, under the existing circumstances, these image data aretransmitted through internet by a personal computer, after object imageshave been converted into image data by a digital still camera. In themode of this kind, however, both a digital still camera and a personalcomputer need to be provided for transmitting image data. In contrast tothis, there is an attempt to mount an image pickup element such as CCDtype image sensor on a cell phone. An attempt of this kind makes itunnecessary to have a digital still camera and a personal computer, andit makes it possible for a cell phone that can be carried convenientlyto pick up images and to send them to a partner.

However, if a cell phone is made to have functions owned by a digitalstill camera which is far greater than the cell phone at this stage, thecell phone itself grows greater in size and becomes heavier, resultingin a problem that it cannot be carried conveniently. Further,manufacturing cost for the cell phone is also increased by an amountequivalent to the increase in its size and weight.

In particular, even when a photographing optical system and an imagepickup element which are primary constituent factors of the digitalcamera are unitized, a photoelectrically-converting section of the imagepickup element is required to be set appropriately on the focusingposition of the photographing optical system, and how to adjust themresults in a problem.

For example, when the image pickup element and the photographing opticalsystem are installed on the same base board, it is considered to bedifficult to incorporate a photoelectrically-converting section of aphotographing element accurately on the focusing position of thephotographing optical system, because of factors such as dispersion of athickness of adhesive agents to be used for the aforesaid installationon the base board and dimensional dispersion of constituent parts.Therefore, for enhancing the focusing position of the photographingoptical system and accuracy of incorporating aphotoelectrically-converting section of a image pickup element, highlyaccurate incorporating technology is required, or a mechanism to adjustthe focusing position separately is needed, which causes a problem of anincrease of manufacture cost. Problems in prior art will be pointed out,referring to the examples.

FIG. 6 is a sectional view showing an example of an image pickup devicein the prior art, wherein image pickup element 110 is arranged on baseboard PC made of glass epoxy resin, and the image pickup element 110 isconnected with image processing IC circuit 111 arranged on the reverseside of the base board PC through many wires W coming from a terminal(not shown) on the upper surface of the image pickup element 110.

First housing 101 is arranged to cover the image pickup element 110, andsecond housing 102 is placed on the first housing 101 so that both ofthem are fixed together to the base board with bolts 103. Infraredabsorption filter 104 is arranged between the first housing 101 and thesecond housing 102.

An upper portion of the second housing 102 is in a cylindrical form, andlens-barrel 105 housing therein lens 106 is mounted on the secondhousing 102, through engagement between female screw 102 a formed insidethe cylindrical upper portion and male screw 105 a formed on thelens-barrel 105, to be adjustable in terms of a position in thedirection of an optical axis. The lens-barrel 105 is provided withdiaphragm portion 105 b that is formed on the upper portion of thelens-barrel 105′.

As stated above, the image pickup device in the prior art is arelatively-large device composed of many parts. Therefore, it naturallyhas a problem of the aforesaid manufacturing cost, and assembling of theparts is time-consuming, while in the course of construction, it isnecessary to adjust relative positions between the image pickup element110 and the lens 106 by rotating the lens-barrel 105. For theseproblems, TOKKAIHEI No. 9-284617, for example, discloses an image pickupdevice wherein an image pickup element and an optical system areunitized.

In the image pickup device mentioned above, the number of parts isreduced by the unitization and the device is made to be compactaccordingly, which makes it easy to mount the device on a cell phone.Incidentally, the image pickup device of this kind is of a structurewherein four corners of the so-called bare chip representing an imagepickup element itself are used for positioning in the direction of anoptical axis of a lens and for positioning in the directionperpendicular to the optical axis of the lens, and thereby, a focusedimage is formed at an appropriate position on aphotoelectrically-converting section of the bare chip. However, fourcorner edges of the bare chip are actually poor in terms of surfaceaccuracy such as flatness and roughness if no action is taken, becauseeach of them is usually a silicone wafer having a thickness of about 0.5mm which is simply cut. Accordingly, for improving positioning accuracywhile using four corner edges of the bare chip, a holding portion for alens section needs to be extended along each surface to be as long aspossible from each of four corners of the bare chip, which causes aproblem that the structure is made to be large in size. When wirebonding pads to be connected with a base board are arranged on thesurface of the bare chip closer to the lens, in particular, these padsmust be avoided, which makes the design of the holding portion to bedifficult.

Further, for solving the problems stated above, there is an attempt toconstruct an image pickup device by providing on a lens a leg portionwhich is extended to the vicinity of a focal length position of the lensand thereby by making the leg portion to touch an image pickup elementdirectly. The attempt of this kind makes it possible to arrange aphotoelectrically-converting section of the image pickup element at thefocusing position of the lens, and thereby, to reduce the time toincorporate the image pickup device greatly.

However, in various apparatuses each being equipped with the compactimage pickup device of this kind, it is supposed that the image pickupdevice is vibrated or it is dropped accidentally and is shocked. Inthese cases, if the leg portion of the lens is in contact with the imagepickup element, there is a fear that the lens is loosened by thevibration or the image pickup element is damaged by the shock.

For this problem, it is considered that the lens is brought in pressurecontact with the image pickup element while giving a prescribed pressure(see TOKKAIHEI No. 9-284617) by a lens holder and the lens and the imagepickup element are fixed by cementing the lens holder to a base board.In this technology, there is a possibility that the lens is loosenedwhen the pressure is reduced by a change with age in thickness ofadhesive agents and in forms of parts, although play between the lensand the image pickup element is restrained. Further, there still is afear the force of the shock makes the lens to damage the image pickupelement.

SUMMARY OF THE INVENTION

The invention has been achieved in view of the problems stated above,and its object is to provide an image pickup device whereinmanufacturing cost is low, the number of parts can be reduced, a size ofthe device can be made small, accurate assembling is possible under noadjustment, and structures for dustproof and moisture-proof are furtherprovided.

The above objects can be achieved by the following structures:

An image pickup device provided on a base board, comprises:

an image pickup element provided on the base board and including aphotoelectrically converting section in which pixels are arranged, aperipheral surface formed around the photoelectrically convertingsection and a side surface crossing the peripheral surface;

an optical member including a lens section to form an image of an objectonto the photoelectrically converting section of the image pickupelement, a leg section to support the lens section and a contact surfaceto be brought in contact with the image pickup element, wherein the lenssection, the leg section and the contact surface are made in a singlebody; and

wherein the optical member is mounted on the image pickup element suchthat the contact surface is brought in contact with the peripheralsurface or with a surface member when the surface member is provided onthe peripheral surface.

An image pickup device provided on a base board, comprises:

an image pickup element provided on the base board and including aphotoelectrically converting section in which pixels are arranged, aperipheral surface formed around the photoelectrically convertingsection and a side surface crossing the peripheral surface;

an optical member including a lens section to form an image of an objecton the photoelectrically converting section of the image pickup element,a leg section to support the lens section and a contact surface to bebrought in contact with the image pickup element, wherein the lenssection, the leg section and the contact surface are made in a singlebody; and

a lens frame to retain the optical member;

wherein the position between the lens section and the photoelectricallyconverting section of the image pickup element in the optical axisdirection is determined by bringing the contact surface in contact withthe peripheral surface or with a surface member when the surface memberis provided on the peripheral surface, and

wherein the position between the lens section and the photoelectricallyconverting section of the image pickup element in the directionperpendicular to the optical axis is determined by mounting the lensframe on the base board and by retaining the optical member with thelens frame.

Further, the above object may be achieved by the following structures:

An image pickup device of the first invention is represented by an imagepickup device arranged on a base board having an image pickup unitplaced on the base board which includes an image pickup element equippedwith a photoelectrically-converting section on which pixels arearranged, a peripheral surface formed around thephotoelectrically-converting section and a side surface that crosses theperipheral surface, and an optical member equipped with a lens sectionwhich forms subject images on the photoelectrically-converting sectionof the image pickup element and with a leg portion that supports thelens section, wherein the leg portion directly touches only theperipheral surface among the surfaces of the image pickup element, ortouches the peripheral surface or a surface material only when thesurface material is provided on the peripheral surface of the imagepickup element.

An image pickup device of the second invention is represented by animage pickup device arranged on a base board having an image pickup unitplaced on the base board which includes an image pickup element equippedwith a photoelectrically-converting section on which pixels are arrangedand a peripheral surface formed around the photoelectrically-convertingsection, an optical member equipped with a lens section which formssubject images on the photoelectrically-converting section of the imagepickup element and with a leg portion that supports the lens section,and lens frame that holds the optical member, wherein the leg portiondirectly touches the peripheral surface of the image pickup element, ortouches the peripheral surface or a surface material when the surfacematerial is provided on the peripheral surface of the image pickupelement, and thereby, the positioning in the direction of an opticalaxis for the lens section and the photoelectrically-converting sectionof the image pickup element is conducted, and the lens frame is providedon the base board, and thereby, the positioning in the directionperpendicular to an optical axis for the lens section and thephotoelectrically-converting section of the image pickup element isconducted.

The image pickup device of the first invention is represented by animage pickup device arranged on a base board having an image pickup unitplaced on the base board which includes an image pickup element equippedwith a photoelectrically-converting section on which pixels arearranged, a peripheral surface formed around thephotoelectrically-converting section and a side surface that crosses theperipheral surface, and an optical member equipped with a lens sectionwhich forms subject images on the photoelectrically-converting sectionof the image pickup element and with a leg portion that supports thelens section, wherein the leg portion directly touches only theperipheral surface among the surfaces of the image pickup element, ortouches the peripheral surface or a surface material only when thesurface material is provided on the peripheral surface of the imagepickup element, and therefore, it is possible to position the lenssection and the image pickup element in the direction of an optical axiswithout using the four corners and sides of the image pickup elementwhich are relatively poor in surface accuracy. Incidentally, the surfacematerial means a glass plate or the like that is stuck on the peripheralsurface, to which, however, the invention is not limited. Incidentally,the peripheral surface of the present invention is a surface exiting onthe substantially same flat surface with the surface of thephotoelectrically converting section of the image pickup element and theside surface is excluded from the peripheral surface.

When a terminal for wiring for connecting the image pickup element tothe base board is formed on the peripheral surface, in particular, ifthe touching point of the leg portion is structured to touch theperipheral surface at a point closer to the photoelectrically-convertingsection than the terminal for wiring, an interference with the terminalfor wiring is controlled while the image pickup element is maintained tobe in a compact construction, and highly accurate positioning can beattained.

Further, if the photoelectrically-converting section is arranged at thecentral portion of the image pickup element, it is possible to secure abroad area to be touched and to attain stable positioning, because anarea that can be touched by the touching point of the leg portion on theperipheral surface can be arranged symmetrically about an optical axisof the lens portion.

Further, if an image processing circuit of the image pickup element isarranged inside the peripheral surface in the inner side of the imagepickup element, it is not necessary to provide the image processingcircuit on the base board on which an image pickup device is to beattached, and the base board can be made compact.

In addition, if there is provided an elastic member that presses theoptical member in the direction of an optical axis, it is possible topress the lens section with appropriate force in the direction of anoptical axis, by using elastic force of the elastic member, and noexcessive stress is caused on a peripheral surface (active area) of theimage pickup element in which a circuit and an element are arranged.

If there is provided a cover member capable of transmitting light atleast partially which is arranged to be closer to a object than from thelens section and presses the lens section through the elastic member,the lens section is not exposed and is protected, which is preferable.

Further, if the portion of the cover member which can transmit light isformed by the material having infrared absorption characteristics, thenumber of parts can be reduced, which is preferable. However, it is alsopossible to coat a film having infrared reflection characteristics onthe surface of the cover member, in place of, or in addition to formingthe cover member with the material having infrared absorptioncharacteristics.

In the image pickup device of the first invention, the leg portion ofthe optical member is sometimes arranged at the position in the vicinityof the photoelectrically-converting section of the image pickup element.However, by providing a first diaphragm that regulates the F number ofthe lens section and a second diaphragm provided at the object sidepositioned from the first diaphragm that regulates peripheral lightflux, it is possible to reduce incidence of unwanted light and therebyto restrain that internal reflection from the leg portion arrives at thephotoelectrically-converting section as a ghost. It is thereby possibleto form images with high image quality.

Further, when the lens section is composed of a positive single lenswhich has, on the object side, a first diaphragm regulating the F numberand has a surface that has a stronger curvature and faces the imageside, it is possible to make a light flux entering aphotoelectrically-converting section of the image pickup element toenter at an angle which is almost vertical, namely, to make it to beclose to a telecentric system, and thereby to obtain images with highimage quality. In addition, by making the lens section to be in a formof a positive lens whose surface having stronger curvature faces theimage side, a distance between a first diaphragm and a principal pointof the lens section can be made long, resulting in the preferablestructure which is more close to the telecentric system.

When the lens section is composed of two or more lenses, the degree offreedom for correction of aberration is enhanced, and images with higherimage quality can be obtained accordingly.

Further, when the lens section includes at least one positive lens andat least one negative lens, it is possible to correct excellentlyvarious aberrations such as spherical aberration and curvature of thefield, by using these positive lens and negative lens. It is furtherpossible to offset influences of changes in refractive index and changesin lens form both caused by temperature changes which tend to be aproblem when the lens is made of a plastic material, and thereby torestrain the fluctuation of a position of the image point caused bytemperature change to be small.

If the lens closest to the image side in the lens section is a positivelens, and a first diaphragm that regulates the F number is arranged tobe closer to the object side than the lens closest to the image side, itis possible to improve telecentric characteristics of a light flux whichenters a photoelectrically-converting section of the image pickupelement.

In addition, if each lens is positioned in the direction perpendicularto an optical axis by engaging the surface provided on each lens of thelens section to be in parallel with its optical axis, optical axes of aplurality of lenses can easily be made to agree with each other.

The image pickup device of the second invention is represented by animage pickup device arranged on a base board having an image pickup unitplaced on the base board which includes an image pickup element equippedwith a photoelectrically-converting section on which pixels are arrangedand a peripheral surface formed around the photoelectrically-convertingsection, an optical member equipped with a lens section which formsobject images on the photoelectrically-converting section of the imagepickup element and with a leg portion that supports the lens section anda lens frame that holds the optical member, wherein the leg portiondirectly touches the peripheral surface of the image pickup element, ortouches the peripheral surface or a surface material when the surfacematerial is provided on the peripheral surface of the image pickupelement, and thereby the lens section and thephotoelectrically-converting section of the image pickup element arepositioned in the direction of an optical axis, and the lens section andthe photoelectrically-converting section of the image pickup element arepositioned in the direction perpendicular to the optical axis withinstallation of the lens frame on the base board, thus, it is possibleto position the lens section and the photoelectrically-convertingsection in the direction of the optical axis without using the fourcorners and sides of the image pickup element which are relatively poorin surface accuracy, and it is possible to attain high accuracy forpositioning at low cost without using the four corners and sides of theimage pickup element which are relatively poor in surface accuracy,because positioning of the lens section and thephotoelectrically-converting section in the direction perpendicular tothe optical axis is attained by installation of the lens frame on thebase board and by retaining the optical member with lens frame.

When a terminal for wiring for connecting the image pickup element tothe base board is formed on the peripheral surface, in particular, ifthe touching point of the leg portion is structured to touch theperipheral surface at a point closer to the photoelectrically-convertingsection than the terminal for wiring, an interference with the terminalfor wiring is controlled while the image pickup element is maintained tobe in a compact construction, and highly accurate positioning can beattained.

Further, if the photoelectrically-converting section is arranged at thecentral portion of the image pickup element, it is possible to secure abroad area to be touched and to attain stable positioning, because anarea that can be touched by the touching point of the leg portion on theperipheral surface can be arranged symmetrically about an optical axisof the lens portion.

Further, if an image processing circuit of the image pickup element isarranged inside the peripheral surface in the inner side of the imagepickup element, it is not necessary to provide the image processingcircuit on the base board on which an image pickup device is to beattached, and the base board can be made compact.

In addition, if there is provided an elastic member that presses theoptical member in the direction of an optical axis for the lens frame,it is possible to press the optical member with appropriate force in thedirection of an optical axis, by using elastic force of the elasticmember, and no excessive stress is caused on a peripheral surface(active area) of the image pickup element in which a circuit and anelement are arranged, which is preferable from the viewpoint ofprotection of the image pickup element. Further, even when great forceis applied on the lens frame in the direction of an optical axis, theforce is not transmitted directly to the image pickup element althoughit is transmitted to the base board, which is preferable from theviewpoint of protection of an image pickup element.

If there is provided a cover member capable of transmitting light atleast partially which is arranged to be closer to a object than from thelens section and presses the lens section through the elastic member,the lens section is not exposed and is protected, which is preferable.

Further, if the portion of the cover member which can transmit light isformed by the material having infrared absorption characteristics, thenumber of parts can be reduced, which is preferable. However, it is alsopossible to coat a film having infrared reflection characteristics onthe surface of the cover member, in place of, or in addition to formingthe cover member with the material having infrared absorptioncharacteristics.

If the optical member is arranged to be capable of being inserted in thelens frame from the object side, fabrication of the lens section iseasy, and it is easy to introduce automatic incorporation.

In the image pickup device of the second invention, the leg portion ofthe optical member is sometimes arranged at the position in the vicinityof the photoelectrically-converting section of the image pickup element.However, by providing a first diaphragm that regulates the F number ofthe lens section and a second diaphragm provided at the object sidepositioned from the first diaphragm that regulates peripheral lightflux, it is possible to reduce incidence of unwanted light and therebyto restrain that internal reflection from the leg portion arrives at thephotoelectrically-converting section as a ghost. It is thereby possibleto form images with high image quality.

Further, when the lens section is composed of a positive single lenswhich has, on the subject side, a first diaphragm regulating the Fnumber and has a surface that has a stronger curvature and faces theimage side, it is possible to make a light flux entering aphotoelectrically-converting section of the image pickup element toenter at an angle which is almost vertical, namely, to make it to beclose to a telecentric system, and thereby to obtain images with highimage quality. In addition, by making the lens section to be in a formof a positive lens whose surface having stronger curvature faces theimage side, a distance between a first diaphragm and a principal pointof the lens section can be made long, resulting in the preferablestructure which is more close to the telecentric system.

When the lens section is composed of two or more lenses, the degree offreedom for correction of aberration is enhanced, and images with higherimage quality can be obtained accordingly.

Further, when the lens section includes at least one positive lens andat least one negative lens, it is possible to correct excellentlyvarious aberrations such as spherical aberration and curvature of thefield, by using these positive lens and negative lens. It is furtherpossible to offset influences of changes in refractive index and changesin lens form both caused by temperature changes which tend to be aproblem when the lens is made of a plastic material, and thereby torestrain the fluctuation of a position of the image point caused bytemperature change to be small.

If the lens closest to the image side in the lens section is appositivelens, and a first diaphragm that regulate the F number is arranged to becloser to the object side than the lens closest to the image side, it ispossible to improve telecentric characteristics of a light flux whichenters a photoelectrically-converting section of the image pickupelement.

In addition, if each lens is positioned in the direction perpendicularto an optical axis by engaging the surface provided on each lens of thelens section to be in parallel with its optical axis, optical axes of aplurality of lenses can easily be made to agree with each other.

Further, to attain the object stated above, an image pickup device ofthe third invention has therein a base board, an image pickup elementequipped with a photoelectrically-converting section having aphotoelectrically-converting section, an optical member equipped with alens section that forms a subject image on thephotoelectrically-converting section of the image pickup element andwith a leg portion that supports the lens section, and an elastic means,and is characterized in that the optical member is urged by the elasticforce of the elastic means toward the image pickup element.

An image pickup device of the fourth invention has therein a base board,an image pickup element equipped with a photoelectrically-convertingsection having a photoelectrically-converting section, an optical memberequipped with a lens section that forms a subject image on thephotoelectrically-converting section of the image pickup element andwith a leg portion that supports the lens section, and a lens frame thatsupports the optical member and is equipped with an elastic means, andis characterized in that the optical member is urged by the elasticforce of the elastic means toward the image pickup element.

An image pickup device of the third invention has therein a base board,an image pickup element equipped with a photoelectrically-convertingsection having a photoelectrically-converting section, an optical memberequipped with a lens section that forms a subject image on thephotoelectrically-converting section of the image pickup element andwith a leg portion that supports the lens section, and an elastic means,and is characterized in that the optical member is urged by the elasticforce of the elastic means toward the image pickup element. Therefore,the optical member and the image pickup element can be positioned easilyin the direction of an optical axis by urging the leg portion of theoptical member by making it to touch the surface of the image pickupelement, for example, and yet, it is possible to urge the optical membertoward the image pickup element with a stable elastic force even whendeformation such as a warp of parts is caused by a change with age, andthereby, it is possible to restrain play of the optical member in thecase of occurrence of vibrations, and thus, damage of the image pickupelement in the case of occurrence of shocks can be restrained.Incidentally, CMOS (Complementary Metal Oxide Semiconductor) ispreferable as the image pickup element, but CCD (Charged Coupled Device)may also be used.

Further, when the elastic force of the elastic means makes the legportion to be in contact with the surface of the image pickup elementfacing the lens section under the load ranging from 5 g to 500 g, damageof the image pickup element can be restrained by appropriate control ofthe elastic force.

If there is provided a cover member which is attached, to be closer to aobject than the lens section, on a lens frame that is fixed on the baseboard, to press the elastic means, and if a part of that cover member iscapable of transmitting light, the lens section can be protected.Namely, the cover member prevents the lens section from being exposed tothe outside, which restrains that the lens section accidentally suffersforce, resulting in damage of the image pickup element.

Further, if the elastic means is structured to be separate from theoptical member and the cover member, what is required to be replaced forthe appropriate control of the elastic force is only the elastic means,which results in cost reduction

If the elastic means is represented by a coil spring, the elastic forcecan be displayed by the coil spring stably for a long time.

Further, if the elastic means is represented by a sheet-shaped memberhaving an opening at its center, it makes it easy to incorporate, and itis preferable in terms of space saving.

If the sheet-shaped member is composed of a member havinglight-shielding characteristics and if the sheet-shaped member also hasa function of a diaphragm regulating the F-number of the lens section,it is not necessary to provide a separate diaphragm, which is preferablein terms of reduction of the number of parts.

Further, if the elastic means is structured to be solid with the covermember, the number of parts is reduced, which is preferable.

Further, if the elastic means is structured to be solid with the opticalmember, the number of parts is reduced, which is preferable.

An image pickup device of the forth invention has therein a base board,an image pickup element equipped with a photoelectrically-convertingsection having a photoelectrically-converting section, an optical memberequipped with a lens section that forms a subject image on thephotoelectrically-converting section of the image pickup element andwith a leg portion that supports the lens section, and a lens frame thatsupports the optical member and is equipped with an elastic means, andis characterized in that the optical member is urged by the elasticforce of the elastic means toward the image pickup element. Therefore,the optical member and the image pickup element can be positioned easilyin the direction of an optical axis by urging the leg portion of theoptical member by making it to touch the surface of the image pickupelement, for example, and yet, it is possible to urge the optical membertoward the image pickup element with a stable elastic force even whendeformation such as a warp of parts is caused by a change with age, andthereby, it is possible to restrain play of the optical member in thecase of occurrence of vibrations, and thus, damage of the image pickupelement in the case of occurrence of shocks can be restrained.Incidentally, CMOS is preferable as the image pickup element, but CCDmay also be used.

Further, when the elastic force of the elastic means makes the legportion to be in contact with the surface of the image pickup elementfacing the lens section under the load ranging from 5 g to 500 g, damageof the image pickup element can be restrained by appropriate control ofthe elastic force.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of an image pickup device of the firstembodiment.

FIG. 2 is a perspective view of the image pickup device shown in FIG. 1.

FIG. 3 is a perspective view of an optical member.

FIG. 4 is a diagram of a bottom surface of the optical member.

FIG. 5 is a diagram of a top surface of an image pickup element.

FIG. 6 is a sectional view showing an example of an image pickup devicein the prior art.

FIG. 7 is a sectional view of an image pickup device of the secondembodiment.

FIG. 8 is an aberration diagram relating to the first example(Example 1) of lens section 1 a of optical member 1 which can be appliedto the embodiments in FIG. 1 and FIG. 7.

FIG. 9 is an aberration diagram relating to the second example (Example3) of lens section 1 a of optical member 1 which can be applied to theembodiments in FIG. 1 and FIG. 7.

FIG. 10 is a sectional view of an image pickup device of the thirdembodiment.

FIG. 11 is an aberration diagram relating to the third example (Example3) of lens sections 1 a′ and 9 a of optical member 19 which can beapplied to the embodiment in FIG. 10.

FIG. 12 is a sectional view of an image pickup device of the thirdembodiment.

FIG. 13 is an aberration diagram relating to the fourth example (Example4) of lens sections 1 a′ and 9 a′ of optical member 19′ which can beapplied to the embodiment in FIG. 12.

FIG. 14 is a sectional view of an image pickup device of the fifthembodiment.

FIG. 15 is a sectional view of an image pickup device comprising amodified embodiment of the elastic means.

FIG. 16 is a perspective view showing an overhauling condition of theoptical member and the elastic member.

FIG. 17 is a sectional view of an image pickup device Of the sixthembodiment.

FIG. 18 is a sectional view of an image pickup device comprising ananother modified embodiment of the elastic means.

FIG. 19 is a sectional view of an image pickup device of the seventhembodiment.

FIG. 20 is a perspective view showing an another modified embodiment.

FIG. 21 is a sectional view of an image pickup device comprising theanother modified embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

A first embodiment of the invention will be explained as follows,referring to the drawings.

FIG. 1 is a sectional view of an image pickup device of the embodimentof the invention. FIG. 2 is a perspective view of the image pickupdevice shown in FIG. 1. FIG. 3 is a perspective view of an opticalmember, and FIG. 4 is a bottom view of the optical member. FIG. 5 is atop view of an image pickup element.

With a transparent plastic material, optical member 1 is composed, in asingle body, of tubular leg portion 1 c, four contact sections 1 d (acontacting surface of the bottom surface of each of the four contactsections 1 d) formed at the lower end of the leg portion 1 c as a partthereof, step portion 1 e formed on a circumference at the upper end ofthe leg portion 1 c, plate-shaped top face section 1 b that covers thetop end of the leg portion 1 c and convex lens section 1 a formed at thecenter of the top face section 1 b as shown in FIGS. 1, 3 and 4.Incidentally, diaphragm plate 3 that is made of a light-shieldingmaterial and has aperture 3 a as a first stop regulating the F number ofconvex lens section 1 a is fixed through gluing on the top face of theface section 1 b and around the convex lens 1 a.

Outside the optical member 1, there is arranged lens frame 4 that ismade of light-shielding material. As is apparent from FIG. 2, the lensframe 4 is provided with prismatic lower portion 4 a and cylindricalupper portion 4 b. The bottom end of the lower portion 4 a is in contactwith the upper side of baseboard PC and is fixed thereon with adhesiveagent B. The top surface of the lower portion 4 a is covered in terms ofperipheral side by partition wall 4 c, and on a circular inner surfaceof the partition wall 4 c, there is engaged leg portion 1 c of theoptical member 1. Therefore, it is possible to position the lens section1 a accurately in the direction perpendicular to the optical axis for aphotoelectrically-converting section 2 d of image pickup element 2 bwhich will be described later, simply by arranging and positioning thebase board PC and lens frame 4 by using, for example, a photo-sensor(not shown) provided on an automatic assembling machine so as tocoincident the center of a cylindrical inner surface of the partitionwall 4 c with the center of the photoelectrically-converting section.

On the other hand, light-shielding plate 5 is attached on the top of theupper portion 4 b of the lens frame 4 with adhesives B. Thelight-shielding plate 5 has, on its center, aperture 5 a representingthe second diaphragm. Filter 7 made of a material having infraredabsorption characteristics is attached under the aperture 5 a of thelight-shielding plate 5 with adhesives B. The light-shielding plate 5and the filter 7 constitute a cover member.

In FIG. 1, elastic member 6 made of a rubber, a spring or the like isarranged between the light-shielding plate 5 and step portion 1 e of theoptical member 1, and the elastic member 6 is subjected to elasticdeformation when the light-shielding plate 5 is attached on the lensframe 4, and the elastic force generated from the elastic deformationpresses the optical member 1 downward in FIG. 1. Therefore, the forcefrom the light-shielding plate 5 is not transmitted directly to imagepickup element 2 b although it is transmitted through the lens frame 4to a base board PC. Incidentally, if the elastic member 6 is formed tobe solid with diaphragm plate 3, the number of parts can be reduced.

In FIG. 5, image pickup unit 2 is composed of image pickup element 2 bsuch as CMOS (Complementary Metal Oxide Semiconductor) type imagesensor. A bottom surface of rectangular sheet-shaped image pickupelement 2 b is stuck on the upper surface of base board PC. At thecenter of the upper surface of the image pickup element 2 b, there isformed a photoelectrically-converting section 2 d on which pixels arearranged two-dimensionally, and peripheral surface 2 a wherein an imageprocessing circuit is structured in image pickup element 2 b and insidethereof is formed around the photoelectrically-converting section. Inthe vicinity of an outer edge of the peripheral surface 2 a that crossesa thin side face at right angles, there are arranged many pads 2 c. Thepad 2 c representing a terminal for wiring is connected to base board PCthrough wire W as shown in FIG. 1. The wire W is connected to aprescribed circuit on the base board PC.

Further, as is clear from FIG. 4 contact section 1 d of optical member 1protrudes from a bottom end of leg portion 1 c to be structured toconstitute a part of the leg portion 1 c, and it is arranged inside pad2 c on the peripheral surface (circumferential surface) 2 a under thecondition that the contact section 1 d only is touching, as shown withdotted lines in FIG. 5. Therefore, with respect to the flatness of asurf ace, the bottom surface (contact surface) of the contact section 1d alone has only to be maintained within a prescribed range.Incidentally, the number of contact sections may be two or threealthough four contact sections are provided in the present embodiment.Since it is arranged so that clearance Δ is formed between the bottomsurface of step portion 1 e of optical member 1 and partition wall 4 cof the lower portion 4 a, under the condition that the contact section 1d is in contact with the peripheral surface 2 a of image pickup element2 b, distance L between the lens section 1 a and thephotoelectrically-converting section 2 d of the image pickup element 2 b(namely, positioning in the direction of an optical axis) is establishedaccurately by a length of leg portion 1 c. Further, since the opticalmember 1 is made of a plastic material, it is also possible to reducethe deviation of focusing position caused by changes in refractive indexof the lens section in temperature changes. Namely, in the case of aplastic lens, the refractive index of the lens is lowered as atemperature goes up, and an image forming position is, changed to befarther from the lens section. On the other hand, since the leg portion1 c is extended by a rise in temperature, it has an effect to reduce thedeviation of focusing position. Incidentally, since the optical member 1in the present embodiment is made of a plastic material whose specificgravity is relatively small, it is lighter than glass that has the samevolume, and is excellent in shock absorbing characteristics. Therefore,even when an image pickup device is dropped accidentally, damage ofimage pickup element 2 b is restrained to the utmost, which is anadvantage.

In the case of the structure wherein optical member 1 can rotate freelyin lens frame 4 as shown in FIG. 5 it is impossible to avoid thatcontact section 1 d interferes with pad 2 c. Therefore, the structurewherein the rotation of the optical member 1 is regulated for assembling(for example, providing a rotation-stopper on lens frame 4) ispreferable.

Operations of the present embodiment will now be explained. Lens section1 a of optical member 1 forms a subject image on thephotoelectrically-converting section 2 d of image pickup element 2 b.The image pickup element 2 b is arranged so that it can transformelectric signals corresponding to an amount of the received light intoimage signals, and to output them through pad 2 c and wire W.

Further, in the present embodiment, since the optical member 1 isattached to a peripheral section 2 a of the image pickup element 2 bwithout being attached to the base board PC, the adjustment for the lenssection 1 a in terms of a focusing position can be made unnecessary atthe time of a set-up by controlling a dimensional accuracy of the legportion 1 c (including the contact section 1 d) of an optical element 1(or an accuracy of the distance L mentioned above).

Since the image pickup device of the present invention is not providedwith an adjusting mechanism to conduct focusing in accordance with theobject distance, as a lens, it is necessary to use a pan-focus lenscapable of obtaining a proper focus point for any object positioned froma long distance to a short distance. Therefore, by coinciding an imageforming point of the lens section 1 a with the position of thephotoelectrically-converting section 2 d of the image pickup element 2 bon the optical axis at the hyper-focal distance U≈f²/(F×2P) (where f isthe focal length of the lens, F is the F-number of the lens and P is thepitch of pixels of the image pickup elements), the focusing can bedeemed from a view point of geometrical optics as the condition that afocus point is obtained for an object at a distance of U/2 from aninfinite point.

For example, in the case that f=3.2 m, F=2.8 and P=0.0056 mm, if theabovementioned distance L is set so as to coincident the image formingpoint of the lens section 1 a at the hyper-focal distanceU≈f²/(F×2P)=0.33 m as a reference object distance with the position ofthe photoelectrically-converting section 2 d of the image pickup element2 b on the optical, axis, a focus point can be obtained for any objectpositioned from a infinite point to a distance of 0.17 m. Further, if itis not necessary to deem the hyper-focal distance as the referenceobject distance and a weight point, for example, is placed an imagequality of an image at a long distance, the reference object distancemay be set at a longer distance than the hyper-focal distance. (Moreconcretely, the above distance L may be set to be a slightly shorterone.)

Here, with regard to an accuracy of the distance L, in order to make itunnecessary to adjust a focal point as the pan-focus lens, it isnecessary to suppress the deviation along the optical axis between theposition of the photoelectrically-converting section 2 d of the imagepickup element 2 b and the image forming point of the lens section 1 aat the reference object distance to an extent of ±0.5×(F×2P), in termsof an air-conversion length (F is the F-number of the image pickup lensand P is the pitch of pixels of the image pickup elements). Morepreferably, it may suppressed to an extent of +0.25×(F×2P). If thedeviation can be suppressed to the above extent, the image quality of anobject at an infinite point or at a closer point can be maintainedproperly.

As stated above, in the present embodiment, contact section 1 d on legportion 1 c of the optical member 1 touches peripheral surface 2 a ofimage pickup element 2 b and thereby lens section 1 a and thephotoelectrically-converting section 2 d of the image pickup element 2 bare positioned in the direction of an optical axis, and therefore, it ispossible to position the lens section 1 a and thephotoelectrically-converting section 2 d of the image pickup element 2 bin the direction of an optical axis without using the four corners ofthe image pickup element 2 b which are relatively poor in surfaceaccuracy. Further, with installation of the lens frame 4 on the baseboard PC based on the position of the photoelectrically-convertingsection 2 d of the image takeup element as a reference point ofpositioning, the lens section 1 a and the photoelectrically-convertingsection 2 d of the image pickup element 2 b are positioned in thedirection perpendicular to the optical axis, thus it is possible toattain high positioning accuracy at low cost without using, in the sameway, the four corners of the image pickup element 2 b which arerelatively poor in surface accuracy.

When pad 2 c and wire W for connecting image pickup element 2 b withbase board PC are formed on peripheral surface 2 a of the image pickupelement 2 b, in particular, if contact section 1 d on leg portion 1 c isarranged to touch peripheral surface 2 a at a position closer to thephotoelectrically-converting section 2 d than pad 2 c, it is possible tosecure a large area for touching for the contact section 1 d whilekeeping the image pickup element 2 b in a compact structure, and therebyto stabilize the optical member 1 and to restrain surface pressure onthe touching surface to be low, thus, interference with pad 2 c and wireW can be controlled while the image pickup element 2 b is protected, andhighly accurate positioning can be attained. When thephotoelectrically-converting section 2 d is arranged at the centralsection of the image pickup element 2 b, an area which can be touched bycontact section 1 d of leg portion 1 c in peripheral surface 2 a can bearranged to be symmetrical about an optical axis of the lens section 1a, and thereby it is possible to secure the bottom area of the contactsection 1 d to be broad, and to attain stable positioning, while keepingthe image pickup element 2 b in a compact structure. It is preferable tomake the center of the photoelectrically-converting section 2 d to agreewith the center of the image pickup element 2 b as shown in FIG. 5. Dueto this, a structure of the whole of the image pickup element 2 b turnsout to be almost symmetrical about an optical axis of lens section 1 aof optical member 1, which can simplify parts shapes. Incidentally, lensframe 4 is glued on base board PC to be sealed hermetically by thatgluing and other two gluing points so that foreign substances may notenter any portions of the image pickup device, thus, it is possible toeliminate an adverse effect of foreign substances on thephotoelectrically-converting section 2 d of the image pickup element 2b. It is preferable that adhesives used for these items havemoisture-proofing characteristics. Due to this, it is possible to avoidsurface deterioration of an image pickup element and of a pad caused byan entry of moisture.

Further, since there is provided elastic member 6 that presses lenssection 1 a in the direction of an optical axis for lens frame 4, it ispossible to press the lens section 1 a with appropriate force in thedirection of an optical axis, by using elastic force of the elasticmember 6, and no excessive stress is caused on peripheral surface 2 a ofimage pickup element 2 b in which a circuit is arranged. Further, evenwhen great force is applied on lens frame 4 in the direction of anoptical axis, the force is not transmitted directly to the image pickupelement 2 b although it is transmitted through the lens frame 4 to thebase board PC. It may be preferable from the viewpoint of protection ofimage pickup element 2 b.

Since a cover member composed of light-shielding plate 5 and filter 7 isarranged to be closer to the object side than lens section 1 a, the lenssection is not exposed and is protected, and sticking of foreignmaterials on the lens surface can also be avoided. Further, since filter7 is made of a material having infrared absorbing characteristics, it isnot necessary to provide an infrared absorption filter separately, andthe number of parts can be reduced, which is preferable. It is alsoconsidered to use a material having infrared absorption characteristicsfor making optical member 1 itself or to coat a film having infraredreflection characteristics on the surface of lens 1 a, in place ofgiving infrared absorption characteristics to the filter 7.

Further, in the course of assembling, the optical member 1 can beinserted in lens frame 4 from the subject side under the condition thatlight-shielding plate 5 is removed from the lens frame 4, and afterthat, the light-shielding plate 5 can be attached on the lens frame 4.This construction makes fabrication of the optical member 1 to be easy,and makes it easy to introduce automatic assembly. In this case, if anair vent hole is formed on lower portion 4 a of the lens frame 4, theoptical member 1 can be inserted in the lens frame 4 easily even when aclearance between the lens frame 4 and the optical member 1 is small.With regard to the air vent hole, however, it is preferable to fill upthe air vent hole with fillers after the insertion and to restrainsurface deterioration for the image pickup element and the pad caused byentrance of foreign materials from the outside or by moisture. Withregard to the fillers in this case, those having light-shieldingcharacteristics to restrain light leakage are preferable. Incidentally,it is possible either to insert optical member 1 after gluing opticalmember 1 on the lens frame 4, or to insert the optical member 1 in thelens frame 4 and then to glue that unit including the optical member 1and the lens frame 4 on the base board PC, which secures the degree offreedom for a process of fabrication. In the case of latter fabricationprocedures, partition wall 4 c of the lens frame 4 can also have afunction to prevent the optical member 1 from coming off.

Since leg portion 1 c of the optical member 1 is arranged in thevicinity of photoelectrically-converting section 2 d of image pickupelement 2 b, there are fears that a light flux that does not contributeto image forming is reflected on the leg portion 1 c and entersphotoelectrically 7 converting section 2 d, causing a ghost image orflare. To prevent this, it is effective to arrange a second diaphragm(aperture 5 a) that regulates a peripheral light flux to be closer tothe object side than a first diaphragm (aperture 3 a) that regulates Fnumber of lens section 1 a, and thereby to reduce entrance of unwantedlight. Incidentally, further effect can be obtained by making aperture 5a of the second diaphragm to be a rectangle, because a field angle isdifferent in each of the shorter side direction, the longer sidedirection and the diagonal direction of the rectangle. Though thisfunction is owned by aperture 5 a of light-shielding plate 5 in thepresent embodiment, it is also possible to form a diaphragm throughcoating or application of a film having light-shielding characteristicsat a location closer to the subject side than filter 7 in addition tonecessary apertures. For the same reason, it is preferable to conductanti-internal-reflection processing on at least a part of the legportion 1 c. The anti-internal-reflection processing includes, forexample, forming a surface whose surface is rough in terms of surfaceroughness and thereby making a light flux contributing to no imageforming to be scattered, anti-reflection coating, or coating of paintshaving low reflection characteristics.

Since diaphragm plate 3 equipped with aperture 3 a is provided on theplane of incidence side of lens section 1 a, it is possible to make alight flux entering photoelectrically-converting section 2 d of imagepickup element 2 b to enter at an angle which is almost vertical,namely, to make it to be close to a telecentric system, and thereby toobtain images with high image quality. In addition, by making a form oflens section 1 a to be in a form of a positive lens whose surface havingstronger curvature faces the image side, a distance between a firstdiaphragm (aperture 3 a) and a principal point of the lens section 1 acan be made long, resulting in the preferable structure which is moreclose to the telecentric system. In the present embodiment, the lenssection 1 a is made to be in a form of a positive meniscus lens. Forobtaining images with higher image quality, it is preferable tostructure a lens portion with plural lenses, as in the third embodimentdescribed later.

FIG. 7 is a diagram showing an image pickup device in the secondembodiment. In the second embodiment, all structures are the same asthose in the embodiment which has been explained above, except thatstructures of a diaphragm plate and of a light-shielding plate arechanged, therefore, other same structures are given the same symbols andexplanation for them will be omitted.

On top of upper portion 4 b of lens frame 4, holding member 5′, havingon its-upper surface, thin light-shielding sheet 8 is fixed withadhesives B, in FIG. 7. In aperture 5 a′ located at the center of theholding member 5′ which is made of a material having light-shieldingcharacteristics, there is fit filter 7′ made of a material havinginfrared absorption characteristics. On an upper edge of the aperture 5a′ of the holding member 5′, there is formed tapered surface 5 b′, andthe holding member 5′ and the filter 7′ are cemented each other byapplying adhesive B on the tapered surface 5 b′. Further, the holdingmember 5′ is provided with tapered section 5 c′ which is protrudeddownward toward the lower portion of the aperture 5 a′ while its insidediameter is reduced stepwise, and its lowermost portion having thesmallest inside diameter constitutes first diaphragm 5 d′. Further,central aperture 8 a of the light-shielding sheet 8 constitutes a seconddiaphragm. The holding member 5′, filter 7′ and light-shielding sheet 8constitute a cover member.

Since a cover member composed of holding member 5′, filter 7′ andlight-shielding sheet 8 is arranged to be closer to the subject sidethan lens section 1 a of optical member 1, the lens section is notexposed and is protected, and sticking of foreign materials on the lenssurface can also be avoided in the present embodiment. Further, sincethe cover member can be formed integrally, it contributes to reductionof the number of parts for the total image pickup device.

Since leg portion 1 c of optical member 1 is arranged in the vicinity ofphotoelectrically-converting section 2 d of image pickup element 2 b inthe same way as in the aforesaid embodiment, there are fears that alight flux that does not contribute to image forming is reflected on theleg portion 1 c and enters photoelectrically-converting section 2 d,causing a ghost image or flare. In the present embodiment, a seconddiaphragm (aperture 8 a) that regulates a peripheral light flux isarranged to be closer to the object side than a first diaphragm 5 a′that regulates F number of lens section 1 a, and thereby entrance ofunwanted light is reduced. Incidentally, further effect can be obtainedby making aperture 8 a of the second diaphragm to be a rectangle,because a field angle is different in each of the shorter sidedirection, the longer side direction and the diagonal direction of thephotoelectrically-converting section 2 d of image pickup element 2 b.

FIG. 8 is an aberration diagram relating to the first example(Example 1) of lens section 1 a of optical member 1 which can be appliedto the embodiment shown in FIGS. 1 and 7. “Table 1” shows lens data of alens section of the present example.

TABLE 1 Example 1 f = 3.21 F = 2.8 2ω = 70.0° Surface No. r d nd vd  1(Diaphragm) ∞ 0.20 *2 −10.428 1.60 1.53000 55.5 *3 −1.539 Asphericsurface coefficient Second surface K = 0.0 A4 = −5.59450 × 10⁻² A6 =−2.90680 × 10⁻² A8 = −4.98890 × 10⁻³ A10 = −1.38940 × 10⁻³ A12 =−1.53220 × 10⁻³ Third surface K = 0.0 A4 =  7.96360 × 10⁻³ A6 =  2.83640× 10⁻⁴ A8 =  3.51190 × 10⁻⁵ A10 =  1.61030 × 10⁻⁵ A12 =  9.74630 × 10⁻⁶

With regard to symbols in the table used in the specification, frepresents a focal length (mm) of the total system, F represents Fnumber, ω represents a half angle of view (°), r represents a radius ofcurvature (mm), d represents a distance between surfaces on an axis(mm), nd represents a refractive index for d line and vd represents Abbenumber.

The symbol “*” in the Surface No. shows an aspheric surface, and thisaspheric surface is expressed by the following expressions under thecondition that the vertex curvature is represented by C, the constant ofthe cone is represented by K and aspheric surface coefficient isrepresented by A₄, A₆, A₈, A₁₀ and A₁₂ in the rectangular coordinateswherein the origin is represented by the vertex of the surface and an Xaxis is represented by the direction of an optical axis.

$\begin{matrix}{X = {\frac{{Ch}^{2}}{1 + \sqrt{1 - {\left( {1 + K} \right)C^{2}h^{2}}}} + {A_{4}h^{4}A_{6}h^{6}A_{8}h^{8}A_{10}h^{10}A_{12}h^{12}}}} & {{Numeral}\mspace{14mu} 1} \\{h = \sqrt{Y^{2} + Z^{2}}} & {{Numeral}\mspace{14mu} 2}\end{matrix}$

FIG. 9 is an aberration diagram relating to the second example (Example2) of lens section 1 a of optical member 1 which can be applied to theembodiment shown in FIGS. 1 and 7. “Table 2” shows lens data of a lenssection of the present example.

TABLE 2 Example 2 f = 3.23 F = 2.8 2ω = 69.6° Surface No. r d nd vd  1(Diaphragm) ∞ 0.20 *2 −11.087 1.60 1.50920 56.5 *3 −1.500 Asphericsurface coefficient Second surface K = 0.0 A4 = −5.80000 × 10⁻² A6 =−2.80000 × 10⁻² A8 = −9.00000 × 10⁻³ A10 = −7.50000 × 10⁻³ A12 =−1.70000 × 10⁻² Third surface K = 0.0 A4 =  9.20000 × 10⁻³ A6 =  7.00000× 10⁻⁴ A8 =  1.00000 × 10⁻⁴ A10 =  7.00000 × 10⁻⁵ A12 =  5.00000 × 10⁻⁵

FIG. 10 is a diagram showing an image pickup device of the thirdembodiment. In the third embodiment, main points different from those inthe second embodiment are that the structure of the optical member hasbeen changed so that a plurality of lens sections may be provided. Withregard to other similar structures including the contact positionbetween the leg portion and the image pickup element, therefore, samesymbols are given to them and explanation therefore will be omitted.

In FIG. 10, optical member 19 is composed of lens 1′ closer to an imageand lens 9 closer to a object. Though the lens 1′ closer to an image isin a form which is similar to that of the optical member shown in FIG.1, a height in the optical axis direction of ring section 1 f′ formed onthe upper portion of the lens 1′ is greater than that in the opticalmember shown in FIG. 1. On upper surface 1 b′ that is inside the ringsection 1 f′ in its radial direction, there is arranged the lens 9closer to a subject through diaphragm plate 3 that regulates the Fnumber. The lens 9 closer to a object is composed of flange section 9 bthat is fitted in an internal circumference of the ring section 1 f′ andof lens section 9 a that is formed at the center. The lens section 9 aof the lens 9 closer to a object is a negative lens, while lens section1 a′ of the lens 1′ closer to an image is a positive lens. Incidentally,the diaphragm plate 3 in the present embodiment functions as a spacerthat regulates a distance between lens sections 1 a′ and 9 a, andaperture 3 a of the diaphragm plate 3 functions as a first diaphragmthat regulate the F number.

since an internal peripheral surface of the ring section 1 f′ of thelens 1′ closer to an image and an outer peripheral surface of the flangesection 9 b of the lens 9 closer to a object are of the same diameterand are in parallel with an optical axis, it is possible to position thelens sections 1 a′ and 9 a in the direction perpendicular to an opticalaxis when these internal peripheral surface and outer peripheral surfaceare engaged, and thereby to make their optical axes to be agreed easily.Incidentally, the lens 9 closer to a object is cemented with the lens 1′closer to an image by adhesives B applied on the circumference of thelens 9.

Holding member 5′ on top of which thin light-shielding sheet 8 is stuckis attached on the upper end of upper portion 4 b of lens frame 4 byadhesives B. Filter 7′ made of a material having light-shieldingcharacteristics is arranged to be fitted in aperture 5 a′ located at thecenter of the holding member 5′ that is made of a material havinglight-shielding characteristics. On an upper edge of the aperture 5 a′of the holding member 5′, there is formed tapered surface 5 b′, and itis possible to cement the filter 7′ with the holding member 5′ byapplying adhesives B on the tapered surface. Further, the holding member5′ is provided with tapered section 5 c′ which is protruded downwardtoward the lower portion of the aperture 5 a′ while its inside diameteris reduced stepwise, and this portion functions as alight-shieldingsection that restrains entrance of unwanted light. Incidentally, thecentral aperture 8 a on the light-shielding sheet 8 constitutes a seconddiaphragm.

FIG. 11 is an aberration diagram relating to the third example (Example3) of lens section (1 a′ and 9 a) of optical member 19 which can beapplied to the embodiment shown in FIG. 10. “Table 3” shows lens data ofthe lens section of the present example.

TABLE 3 Example 3 f = 3.22 F = 2.8 2ω = 63.2° Surface No. r d nd vd *11.332 0.80 1.49200 57.0  2 (Diaphragm) 0.893 0.30 *3 ∞ 0.30 *4 −3.9831.30 1.49200 57.0 *5 −1.009 Aspheric surface coefficient First surface K= −1.00900 × 10⁻² A4 =  6.72900 × 10⁻² A6 = −7.67070 × 10⁻² A8 = 1.34680 × 10⁻¹ A10 = −9.41020 × 10⁻² A12 =  6.56810 × 10⁻² Secondsurface K =  9.62490 × 10⁻³ A4 =  1.38900 × 10⁻¹ A6 = −2.64240 × 10⁻¹ A8=  2.65220 × 10⁺⁰ A10 = −3.53590 × 10⁻¹ A12 = −8.27250 × 10⁻² Fourthsurface K = −1.00000 × 10⁻² A4 = −6.43510 × 10⁻² A6 = −3.56320 × 10⁻¹ A8=  2.02750 × 10⁻¹ A10 = −6.60380 × 10⁻¹ A12 = −3.70030 × 10⁻¹ Fifthsurface K = −1.44350 × 10⁻¹ A4 =  7.14590 × 10⁻² A6 = −2.15930 × 10⁻¹ A8=  4.23870 × 10⁻¹ A10 = −3.76120 × 10⁻¹ A12 =  1.30790 × 10⁻¹

FIG. 12 is a diagram showing an image pickup device of the fourthembodiment. Even in the fourth embodiment, main points different fromthose in the first embodiment and the second embodiment are that thestructure of the optical member has been changed so that a plurality oflens sections may be provided. With regard to other similar structures,therefore, same symbols are given to them and explanation therefore willbe omitted.

In FIG. 12, optical member 19′ is composed of lens 1′ closer to an imageand lens 9′ closer to a subject both being made of a plastic material.Though the lens 1′ closer to an image is in a form which is similar tothat of the optical member 1 shown in FIG. 1, a height in the opticalaxis direction of ring section 1 f′ formed on the upper portion of thelens 1′ is greater than that in the optical member 1. On upper portionof upper surface section 1 b′, there is arranged the lens 9′ closer to aobject through diaphragm plate 3 that regulates the F number. The lens9′ closer to a subject is composed of cylinder section 9 c′ that isfitted with an outer peripheral surface of ring section 1 f′, lenssection 9 a′ that is formed at the center and step portion 9 b′ that isprovided on an outer peripheral surface of lens portion 9 a′. The lenssection 9 a′ of the lens 9′ closer to a object is a negative lens, whilelens section 1 a′ of the lens 1′ closer to an image is a positive lens.Incidentally, the diaphragm plate 3 functions as a spacer that regulatesa distance between lens sections 1 a′ and 9 a′.

In the present embodiment, elastic member 6 is in contact with lens 9′closer to a subject and with step portion 9 b′, and therefore, itselastic force is transmitted from the lens 9′ closer to a subject tolens 1′ closer to an image through diaphragm plate 3. since an outerperipheral surface of the ring section 1 f′ of the lens 1′ closer to animage and an internal peripheral surface of the cylinder section 9 c′ ofthe lens 9′ closer to a subject are of the same diameter and are inparallel with an optical axis, it is possible to position the lenssections 1 a′ and 9 a′ in the direction perpendicular to an optical axiswhen these outer peripheral surfaces are engaged, and thereby to maketheir optical axes to be agreed easily. Incidentally, the lens 9′ closerto a subject is cemented with the lens 1′ closer to an image byadhesives B applied on the lower end of cylinder section 9 c′.

FIG. 13 is an aberration diagram relating to the fourth example (Example4) of lens section (1 a′ and 9 a′) of optical member 19′ which can beapplied to the embodiment shown in FIG. 12. “Table 4” shows lens data ofthe lens section of the present example.

TABLE 4 Example 4 f = 2.30 F = 2.4 2ω = 94.0° Surface No. r d nd vd *19.231 1.00 1.49700 56.0  2 (Diaphragm) 1.230 2.20 *3 ∞ 0.20 *4 2.2431.70 1.49700 56.0 *5 −2.240 Aspheric surface coefficient First surface K=  3.72320 × 10⁻² A4 = −2.20320 × 10⁻³ A6 =  1.10670 × 10⁻⁴ Secondsurface K = −1.57520 × 10⁻¹ A4 = −9.78620 × 10⁻³ A6 =  8.00560 × 10⁻³Fourth surface K =  8.65710 × 10⁻¹ A4 = −1.36460 × 10⁻² A6 =  5.99080 ×10⁻³ Fifth surface K = −6.40440 × 10⁻¹ A4 =  1.83630 × 10⁻² A6 = 2.45110 × 10⁻²

In the present example, at least one positive lens 1 a′ and at least onenegative lens 9 a′ are provided, and thereby, correction of sphericalaberration and of curvature of field can be conducted satisfactorily.Further, correction of chromatic aberration is also easy. By combiningpositive lens 1 a′ and negative lens 9 a′, it is also possible to canceladverse effects of changes in refractive index and in lens form bothcaused by temperature changes which tend to be a problem when a lens ismade of a resin material, and thereby to restrain fluctuations inpositions of an image point caused by temperature changes to be small.

When an optical system for photographing is composed of two or morelenses as in lens sections 1 a′ and 9 a′, the degree of freedom forcorrection of aberration is increased, which makes it possible to obtainimages with high image quality.

Further, if lens section 1 a′ closest to an image is a positive lens,and a diaphragm (aperture 3 a) that regulates the F number is arrangedto be closer to a object than lens section 1 a′ closest to an image, itis possible to improve telecentric characteristics of a light flux thatenters photoelectrically-converting section 2 d of, image pickup element2 b. When two lenses are used as in the third embodiment and fourthembodiment, it is possible to make an adjustment relating to a focusingposition in assembly to be unnecessary, by controlling not onlydimensions of the leg portion 1 c′ of the lens 1′ closer to an image(including contact portion 1 d′) but also a distance between the lens 9closer to a subject and the lens 1′ closer to an image accurately.Incidentally, with regard to the distance between the lens 9 closer to asubject and the lens 1′ closer to an image, fine correction for thedistance can be made by changing a thickness of diaphragm plate 3.

Incidentally, independently of the embodiment stated above, lens 9 or 9′closer to a subject may also be a positive lens, a tele-converter or awide-converter. When higher image quality is desired, a lens section mayalso be composed of three lenses or more. Further, when the lens sectionis constituted with a zoom lens composed of plural lens groups, a focallength may be made to be variable to cope with broader application forphotographing.

Next, various embodiments of the elastic member will be explained.

In the fifth embodiment shown FIG. 14, the elastic member 6 made of acoil spring is arranged between the light-shielding plate 5 and stepportion 1 e of the optical member 1, and the elastic member 6 issubjected to elastic deformation when the light-shielding plate 5 isattached on the lens frame 4, and the elastic force generated from theelastic deformation presses the optical member 1 downward in FIG. 14.Therefore, the force from the light-shielding plate 5 is not transmitteddirectly to image pickup element 2 b although it is transmitted to baseboard PC.

Further, touching point 1 d of optical member 1 is in a shape shown inFIG. 4 mentioned above, and it is protruded from the lower end of legportion 1 c to constitute a part of the leg portion 1 c. In the presentembodiment, touching point 1 d is arranged under the condition that thetouching point 1 d only is in contact with the inside of pad 2 c atperipheral surface 2 a of image pickup element 2 b, as shown with dottedlines in FIG. 5. Therefore, with regard to the flatness of the surface,the bottom surface of the touching point 1 d only has to be maintainedwithin a prescribed range. The number of leg portions 1 c (touchingpoint 1 d) is four, and the center of gravity of the optical member 1comes to its center, therefore, when individual optical member 1 isplaced on a flat surface, it can be said that a position and a shapewhich make an optical axis of lens section 1 a to be perpendicular tothe flat surface are provided. Therefore, even when a clearance existsbetween an inner peripheral surface of lens frame 4 and an outerperipheral surface of optical member 1, the optical axis crosses thephotoelectrically-converting section 2 d of image pickup element 2 b atright angles when leg portion 1 c is brought into contact withperipheral surface 2 a of the image pickup element 2 b, thus, it ispossible to obtains images with high image quality. On the rear side ofthe peripheral surface 2 a (bottom surface side in FIG. 1) in this case,there is provided an unillustrated circuit of an image pickup element(including a signal processing circuit), but processing by the circuitis not affected by the contact of the touching point 1 d.

Now, let the touching position of touching point 1 d be studied. Forexample, when an effective pixel area is made to be smaller slightly bythe total pixel area, a corner section 2 g in the surface of thephotoelectrically-converting section 2 d shown in FIG. 5 becomes an areawhich has no connection with image forming. In that case, therefore,even when the touching point 1 d is made to touch an area of the corner2 g within the surface of the photoelectrically-converting section 2 d,the risk for the image pickup power of image pickup element 2 b to beaffected is less. Incidentally, whichever of peripheral surface 2 a orthe surface of the photoelectrically-converting section 2 d is touched,it is preferable that the load from touching point 1 d is not more than500 g (not more than 1000 g/mm² in terms of surface pressure). That isbecause of a risk that image pickup element 2 b is damaged if this load(surface pressure) is exceeded. When a blurred image caused byvibrations is considered, however, the load from the touching point 1 dthat is 5 g or more is desirable. The load of this kind can becontrolled appropriately, by selecting a wire diameter and the number ofturns of coil spring 6 representing an elastic means, as describedlater.

In the present embodiment, there is formed clearance A between a bottomsurface of step portion 1 e of optical member 1 and partition wall 4 cof lower portion 4 a of lens frame 4 under the condition that thetouching point 1 d is in contact with peripheral surface 2 a of imagepickup element 2 b. Therefore, distance L between lens section 1 a andthe photoelectrically-converting section 2 d of image pickup element 2 b(namely, positioning in the optical axis direction) can be setaccurately by a length of leg portion 1 c. Though four touching pointsin four locations are provided in the present embodiment, the number oflocations may be one location—three locations. Further, if theinterference with, pad 2 c can be avoided, a ring-shaped contact sectionthat is running along cylindrical leg portion 1 c of optical member 1will do.

Further, since there is provided elastic means 6 that presses stepportion 1 e of optical member 1 with a prescribed elastic force in theoptical axis direction, it is possible to use elastic force of theelastic means 6 to press leg portion 1 c (touching point 1 d) with anappropriate touching force (force corresponding to the load from 5 g to500 g stated above) to peripheral surface 2 a of image pickup element 2b along the optical axis direction for lens frame 4, and therefore, theoptical member 1 and the image pickup element 2 b can be positionedeasily in the direction of an optical axis, and yet, it is possible tourge the optical member 1 against the image pickup element 2 b with astable elastic force, even when deformation such as a warp of parts iscaused by a change with age, and thereby, to restrain play of theoptical member 1 in the case of occurrence of vibrations, and thus, noexcessive stress is caused on peripheral surface 2 a of the image pickupelement 2 b in which a circuit are arranged, when shocks are caused.Even when a great force such as an impact force is applied in thedirection of an optical axis of lens frame 4, the force is nottransmitted directly to the image pickup element 2 b although it istransmitted through the lens frame 4 to base board PC, which ispreferable from the viewpoint of protection of the image pickup element2 b. Incidentally, although urethane and sponge are considered as theelastic means 6, a spring made of metal which can display a stableelastic force for a long time is preferable.

FIG. 15 is a sectional view of an image pickup device includingvariations of an elastic means, and FIG. 16 is a perspective viewshowing an optical member and an elastic means which are disassembled.Elastic means 16 shown in FIG. 15 is made of a material havinglight-shielding characteristics, and it is arranged to display thefunction to stop down in place of diaphragm plate 3 shown in FIG. 14. Tobe more concrete, the elastic means 16 made of resin is a sheet-shapedmember which is almost disc-shaped having aperture (diaphragm) 16 a atthe center, and four protrusions 16 b are protruded toward the outsidein the radial direction from the circumference of the elastic means 16at regular intervals. On the other hand, on ring section 11 f formed onthe top of the optical member, there are formed cut-outs 11 g eachcorresponding to each of the protrusions 16 b. By making the cut-outs 11g to be engaged with the protrusions 16 b, the elastic means 16 ismounted on the ring section 11 f to be fitted therein. Further, in thecase of mounting the light-shielding plate 15, when each protrusion 16 bis pressed downward by protrusion 15 c formed on the bottom surface ofthe light-shielding plate 15, the protrusion 16 b is deformedelastically so that the optical member 11 may be urged againstperipheral surface 2 a of image pickup element 2 b with the prescribedelastic force. Other structures are the same as those in the embodimentshown in FIG. 14, and explanation therefore will be omitted accordingly.

FIG. 17 is a diagram showing an image pickup device relating to thesixth embodiment. In the sixth embodiment, only difference from theembodiment stated above is a change of the structure for a diaphragmplate and a light-shielding plate, and other structures which are thesame as those in the aforesaid embodiment are given the same symbols,and explanation therefore will be omitted.

On top of upper portion 4 b of lens frame 4, holding member 5′, havingon its upper surface, thin light-shielding sheet 8 is fixed withadhesives B, in FIG. 17. In aperture 5 a′ located at the center, of theholding member 5′ which is made of a material having light-shieldingcharacteristics, there is fit filter 7′ made of a material havinginfrared absorption characteristics. On an upper edge of the aperture 5a′ of the holding member 5′, there is formed tapered surface 5 b′, andthe holding member 5 and the filter 7′ are cemented each other byapplying adhesive B on the tapered surface 5 b′. Further, the holdingmember 5′ is provided with tapered section 5 c′ which is protrudeddownward toward the lower portion of the aperture 5 a′ while its insidediameter is reduced stepwise, and its lowermost portion having thesmallest inside diameter constitutes first diaphragm 5 d′. Further,central aperture 8 a of the light-shielding sheet 8 constitutes a seconddiaphragm. The holding member 5, filter 7′ and light-shielding sheet 8constitute a cover member.

Since a cover member composed of holding member 5′, filter 7′ andlight-shielding sheet 8 is arranged to be closer to the subject sidethan lens section 1 a of optical member 1, the lens section is notexposed and is protected, and sticking of foreign materials on the lenssurface can also be avoided in the present embodiment. Further, sincethe cover member can be formed integrally, it contributes to reductionof the number of parts for the total image pickup device.

Since leg portion 1 c of optical member 1 is arranged in the vicinity ofthe photoelectrically-converting section 2 d of image pickup element 2 bin the same way as in the aforesaid embodiment, there are fears that alight flux that does not contribute to image forming is reflected on theleg portion 1 c and enters the photoelectrically-converting section 2 d,causing a ghost image or flare. In the present embodiment, a seconddiaphragm (aperture 8 a) that regulates a peripheral light flux isarranged to be closer to the object side than a first diaphragm 5 a′that regulates F number of lens section 1 a, and thereby entrance ofunwanted light is reduced. Incidentally, further effect can be obtainedby making aperture 8 a of the second diaphragm to be a rectangle,because a field angle is different in each of the shorter sidedirection, the longer side direction and the diagonal direction of thephotoelectrically-converting section 2 d of image pickup element 2 b.

Further, in the present embodiment again, there is provided elasticmeans 6 representing an urging member that presses step portion 1 e ofoptical member 1 in the optical axis direction with a prescribed elasticforce, and therefore, it is possible to stress leg portion 1 c (touchingpoint 1 d) against peripheral surface 2 a of image pickup element 2 bwith an appropriate touching force (aforesaid touching force rangingfrom 5 g to 500 g) in the direction of an optical axis for lens frame 4,by using an elastic force of the elastic means 6, thus, no excessivestress is caused on peripheral surface 2 a of the image pickup element 2b in which a circuit is arranged, and no play of optical member 1 iscaused by vibrations.

FIG. 18 is a sectional view of an image pickup device including anothervariation of an elastic means. Elastic means 26 in FIG. 18 is unitedintegrally with a holding member, namely, with a cover member. As isclear from FIG. 18, holding member 26 is made of resin material which iseasily deformed elastically, such as elastomer resin, and four (twoprotrusions only are illustrated) protrusions (elastic means) 26 e areformed on the bottom surface of the holding member 26 at regularintervals, which is only difference from holding member 5′ in FIG. 17.When the holding member 26 is stuck (B) on lens frame 4, the protrusions26 e are deformed elastically, and thereby, optical member 1 is urgedagainst peripheral surface 2 a of image pickup element 2 b with aprescribed elastic force. Other structures are the same as those in theembodiment shown in FIG. 17, and explanation therefore will be omittedaccordingly.

FIG. 19 is a diagram showing an image pickup device relating to theseventh embodiment. In the seventh embodiment, only difference from theembodiment shown in FIG. 14 is that the structure of the optical memberhas been changed so that it has a plurality of lenses, and other samestructures including the touching point between the leg portion and theimage pickup element are given the same symbols, and explanationtherefore will be omitted.

In FIG. 19, optical member 19 is composed of lens 1′ closer to an imageand lens 9 closer to a subject. Though the lens 1′ closer to an image isin a form which is similar to that of the optical member shown in FIG.14, a height in the optical axis direction of ring section 1 f′ formedon the upper portion of the lens 1′ is greater than that in the opticalmember shown in FIG. 14. On upper surface 1 b′ that is inside the ringsection 1 f′ in its radial direction, there is arranged the lens 9closet to a subject through diaphragm plate 3 that stipulates the Fnumber. The lens 9 closer to a subject is composed of flange section 9 bthat is fitted in an internal circumference of the ring section 1 f′ andof lens section 9 a that is formed at the center. The lens section 9 aof the lens 9 closer to a subject is a negative lens, while lens section1 a′ of the lens 1′ closer to an image is a positive lens. Incidentally,the diaphragm plate 3 in the present embodiment functions as a spacerthat regulates a distance between lens sections 1 a′ and 9 a, andaperture 3 a of the diaphragm plate 3 functions as a first diaphragmthat stipulates the F number.

Since an internal peripheral surface of the ring section 1 f′ of thelens 1′ closer to an image and an outer peripheral surface of the flangesection 9 b of the lens 9 closer to a subject are of the same diameterand are in parallel with an optical axis, it is possible to position thelens sections 1 a′ and 9 a in the direction perpendicular to an opticalaxis when these internal peripheral surface and outer peripheral surfaceare engaged, and thereby to make their optical axes to be agreed easily.Incidentally, the lens 9 closer to a subject is cemented with the lens1′ closer to an image by adhesives B applied on the circumference of thelens 9.

Holding member 5′ on top of which thin light-shielding sheet 8 is stuckis attached on the upper end of upper portion 4 b of lens frame 4 byadhesives B. Filter 7′ made of a material having light-shieldingcharacteristics is arranged to be fitted in aperture 5 a′ located at thecenter of the holding member 5′ that is made of a material havinglight-shielding characteristics. On an upper edge of the aperture 5 a′of the holding member 5′, there is formed tapered surface 5 b′, and itis possible to cement the filter 7′ with the holding member 5′ byapplying adhesives B on the tapered surface. Further, the holding member5′ is provided with tapered section 5 c′ which is protruded downwardtoward the lower portion of the aperture 5 a′ while its inside diameteris reduced stepwise, and this portion functions as a light-shieldingsection that restrains entrance of unwanted light. Incidentally, thecentral aperture 8 a on the light-shielding sheet 8 constitutes a seconddiaphragm.

Further, in the present embodiment again, there is provided elasticmeans 6 representing an urging member that presses step portion 1 e′ ofoptical member 19 in the optical axis direction with a prescribedelastic force, and therefore, it is possible to stress leg portion 1 c′(touching point 1 d′) against peripheral surface 2 a of image pickupelement 2 b with an appropriate touching force (aforesaid touching forceranging from 5 g to 500 g) in the direction of an optical axis for lensframe 4, by using an elastic force of the elastic means 6, thus, noexcessive stress is caused on peripheral surface 2 a of the image pickupelement 2 b in which a circuit is arranged, and no play of opticalmember 19 is caused by vibrations.

FIG. 20 is a perspective view of another variation of an elastic means.Elastic means 36 in FIG. 20 is united integrally with an optical member,and it can be incorporated for example, in the image pickup device inFIG. 14 from which elastic means 6 is eliminated. As is clear from FIG.20, four protrusions (elastic means) 36 f (three protrusions only areshown) and arm sections 36 g supporting the protrusions are formed onstep portion 36 e of optical member 36, which is only difference fromthe optical member 1 in FIG. 14. As shown in FIG. 14, under thecondition that optical member 36 is incorporated, protrusions 36 g arebrought into contact with a bottom surface of light-shielding plate 5(FIG. 14), and thereby, cantilever arm 36 g is deformed elastically, andan elastic force generated therefrom urges the optical member 1 againstperipheral surface 2 a of image pickup element 2 b with a prescribedelastic force (FIG. 14). Other structures are the same as those in theembodiment shown in FIG. 14, and explanation therefor will be omittedaccordingly.

FIG. 21 is a sectional view of an image pickup device including anothervariation of an elastic means. An elastic means in FIG. 21 is unitedintegrally with a lens frame. As is clear from FIG. 21, four cut-outs 46d (two cut-outs only are shown) are formed on upper half section 46 b oflens frame 46 at regular intervals, and lower end of arm 46 e thatextends to be in parallel with an optical axis is connected with abottom edge of the cut-out 46 e in FIG. 21. On the upper end of the arm46 e, there is formed protruded section 46 f which is protruded in thedirection perpendicular to the optical axis direction and has a sectionthat is almost in a shape of a triangle. Incidentally, it is preferablethat an upper portion of step portion 1 e of the optical member 1 is ina tapered shape. The arm 46 e and the protruded section 46 f constitutean elastic means.

When inserting optical member 1 into lens frame 46 attached on baseboard PC from the upper side in FIG. 21, step portion 1 e touchesprotruded section 46 f, and the arm 46 e is deformed elastically to beexpanded outward to be perpendicular to an optical axis, which makes iteasy to incorporate the optical member 1. On the other hand, when theoptical member 1 is incorporated up to the position shown in FIG. 21,deformation of the arm 46 e is restored. However, the shape of theprotruded section 46 f is determined so that the restoration mentionedabove is not perfect and the deformation may remain slightly. Therefore,the elastic force resulted from the remained deformation makes theprotruded section 46 f to urge the step portion 1 e in the arroweddirection, and thereby, the optical member 1 is urged against peripheralsurface 2 a of image pickup element 2 b with a prescribed elastic force.Other structures are the same as those in the embodiment shown in FIG.14, and explanation therefor will be omitted-accordingly. Incidentally,in the present embodiment, sufficient function for dust-proof andmoisture-proof cannot be displayed as it is, because of the structure toform the arm 46 e and protruded section 46 f. Contrary to this, it ispossible to make the desired function for dust-proof and moisture-proofto work by covering a clearance of the elastic structure (46 e and 46 f)of lens frame 46 with a separate member.

As another example of the elastic means, a combination of a corrugatedspring and a disc spring can be used in addition to the foregoing.

The invention has been explained above, referring to the embodiment towhich, however, the invention is not limited, and modification andimprovement for the invention can naturally by made. For example, thoughthe connection between the image pickup element 2 b and the base boardPC is carried out by wire W in the present embodiment, it is alsopossible to consider the structure wherein wiring creeps inside imagepickup element 2 b and signals are taken out of the rear side (oppositeto the photoelectrically-converting section) or the side of the imagepickup element 2 b. The structure of this kind makes it possible tosecure a broad peripheral surface of the image pickup element and towire easily. Further, though an image pickup unit is composed only ofimage pickup elements representing bare chips in the present embodiment,it is also possible to structure the image pickup unit of a solid typeby gluing a sheet material such as glass on the upper surface or thebottom surface of the image pickup element. An image pickup device ofthe invention is considered to be capable of being incorporated invarious items such as a cell phone, a personal computer, PDA, an AVapparatus, a TV set and a household electric appliance.

The present invention makes it possible to provide an image pickupdevice wherein cost is low, the number of parts can be reduced, a sizeis small, assembling is accurate despite no adjustment, and dust-proofand moisture-proof structures are provided.

1. An image pickup apparatus, comprising: a base board; an image pickupelement fixed on the base board and including a photoelectricallyconverting section and an upward-facing contact surface; an opticalmember including a lens section to form an image of an object on thephotoelectrically converting section of the image pickup element, a legsection to support the lens section and a downward-facing contactsurface provided to the leg section so as to be brought in contact withthe upward-facing contact surface of the image pickup element; a lensframe fixed to the base board so as to surround the optical member andhaving an opening section; a cover member having an aperture throughwhich light enters the lens section of the optical member and fixed onthe opening section of the lens frame such that a space is providedbetween the cover member and the optical member; and an elastic memberprovided in the space between the optical member and the cover member sothat when the cover member is fixed on the lens frame, the elasticmember presses the optical member toward the image pickup element withan elastic force and the downward-facing contact surface of the opticalmember is in pressure contact with the upward-facing contact surface ofthe image pickup element.
 2. The image pickup apparatus of claim 1,wherein the elastic member is a separate body made of an elasticmaterial provided between the optical member and the cover member. 3.The image pickup apparatus of claim 2, wherein the elastic material isone of a rubber and a resin.
 4. The image pickup apparatus of claim 1,wherein the elastic member is a coil spring.
 5. The image pickupapparatus of claim 1, wherein the elastic member is a sheet-shapedmember provided between the optical member and the cover member so as tocreate an elastic force.
 6. The image pickup apparatus of claim 5,wherein the sheet-shaped member is made of a material having a lightshielding capability and has an opening at a central portion thereof soas to be used as a diaphragm to regulate the F-number of the lenssection.
 7. The image pickup apparatus of claim 1, wherein the elasticmember is a protrusion which is made of a resin and is provided betweenthe optical member and the cover member.
 8. The image pickup apparatusof claim 1, wherein the protrusion is made in one body with the covermember.
 9. The image pickup apparatus of claim 1, wherein the elasticmember is an arm member protruded from optical member so as to come incontact with the lens frame.
 10. The image pickup apparatus of claim 1,wherein the elastic member is an arm member protruded from the lensframe so as to engage with the optical member.
 11. The image pickupapparatus of claim 1, wherein when the cover member is fixed on the lensframe, the downward-facing contact surface is brought in pressurecontact with the upward-facing contact surface of the image pickupelement with a weight of 5 g to 500 g.
 12. The image pickup apparatus ofclaim 1, wherein the lens section, the leg section and thedownward-facing contact surface are made in a single body.